Anderton '64 reissue JTM145 - any info?

[Littlewyan]

I reckon the Tone Stack is like the attached which is the same as what Jazzkramer drew on paper. It makes perfect sense this way and will give the same frequency response as JTM45 with all of the knobs on 5.

[jazzkramer]

Thank you Littlewyan!
So in the night I will concentrate to check the main board... will be a huge work... it will take several days I think.

[Matec]

Good morning guys.

I see that you walked busy today, and that's good.

I saw the scheme that has been changed by you, and it makes perfect sense.

But I have my doubts and would like jazzkramer made ​​a last group of tests, so I was satisfied. Is it possible?

Matec.

[jazzkramer]

Yes Matec sure. I'm little busy with other things, so maybe I will not reply soon, but tell me

And, checking the main board, at the moment I found a little difference:

So: The green area is already checked. The purple wire is the one I see in the board and not in your schematic, so I added it. The dashed wire is the one I don't see on the board so I deleted from your schematic.

[Matec]

Thanks for the correction. I'll fix the schema.

The test is simple and will convince me if I'm wrong.

In toneboard with one end of the terminal always get 2 CON101. (The meter in the scale of resistance, 200k).

Measure the resistance in the two terminals of C103

Measure the resistances in the two terminals of R101.

Measure the resistances in the two terminals of R103.

And write the results.

It's just.

Thank you!

[jazzkramer]

Ok: so I put one of the tester probe to the middle pin of the CON101

the other tester probe:

(I spell terminas as if you where looking to the amp from the front, when all assembled)

C103 Upper terminal infinites ohms; down terminal 12,1K

R101. right term reads 12,1K; left term reds 112,6K

R103. Upper term reads 0; Down teminal reads 2,1K

Is it correct?

[Matec]

Yes, I am completely convinced!

His scheme is correct.

I will correct in my schema, and post later.

Thank you!

Matec

[Matec]

Here is the scheme with the necessary corrections.

But I remembered something that does not allow this to be the definitive schema.

And again I will need the help of jazzkramer to solve this question. Care is needed in this test!

Here is the JTM1 SCHEMATIC: (Corrected, 03/09/2014.)

[img625]http://s26.postimg.cc/k4sll6lft/JTM1_28_08_2014_B.png[/img]
(To see the full size image, click on the above link and open in new tab.)

Matec

[jazzkramer]

Ok Matek you did a great job!

All the green part is correct while it seems that in the components between V2B and V3 there are some mistakes. I will better check but now I have to stop.

To better verify, I ask you if you can maybe post a better resolution image, I mean it's not simple to read all the components numbers in that part.

Ok I don't know If I can go on today... sorry, in the worst case I will keep on tomorrow, but don't worry I will finish checking all things and if you have doubts, we will check with the tester as we did with the Tone pcb.

Thanks, jazzkramer

[Matec]

How's the name of this topic?

Do not want to leave forgotten those wonderful photos of our friend build.

Then with the information contained in them did a little preliminary scheme, the JTM145. Missing key information for complete circuit, but which are contained here are proven.

I'm finding that after this topic, Marshall will move to love us ...

Components with some kind of doubt => ???

Of course, if anyone finds errors in the scheme, we will fix them.

Matec .


[img488]http://s26.postimg.org/qv2lnuayx/CS_JTM1_AG_13_08_2014b.png[/img]


Corrected!

[Thomas_H]

Hi you all,
this thread is amazing, all that good quality pictures!

Matec I took a quick look at the board, and it looks similar to the JTM1 to me...

Just couldn't find C13 in your schematic. It looks like it is between R20 and ground.

I'm at this point of the circuit so far...

Cheers,
Thomas

[Matec]

Hi Thomas!

You are right!

I've been distracted these days

I'll fix the schema of JTM145. Probably there are other errors, but soon will be corrected.

Thank you!

[jazzkramer]

Ok here are the progress.... Now going to sleep:

In green the checked part. The part between V2B and V3 seems to me very different. I'm too tired to make a better drawing now, I will do after finishing checking.

Maybe I mistaken something, I will re-check everithing.

I'm not checking any component value now, only component names and schematic, then, when the schematic will be ok, I will check all component values again.

I will go on as soon as possible

Bye, jazzkramer.

[MHProd]

Do you guys still need pics of the JTM1?

[jazzkramer]

Hi MHProd, thank you, I think at the moment we don't. I have a JTM1 board in my hand and I'm trying to check Matec schematic.

We would need JTM145 tone PCB photos and input PCB both sides.

Thanks, bye, jazzkramer.